The project's aims are: (a) To see whether previous reports that systematic muscle relaxation training produces blood pressure reductions in essential hypertensives can be replicated; (b) To identify the type of hypertensive most likely to respond favorably to relaxation training. With these aims in view the following characteristics of hypertensives are being investigated: (a) Presence of high baseline EMG (muscle tension) levels; (b) Presence of low peripheral temperature; (c) Evidence of strong pressor responses to environmental stresses; (d) Evidence of marked pressor episodes in response to emotions such as anger or anxiety; (e) Evidence of marked pressure drops with sleep onset. Our biofeedback approach to relaxation involves the training of a "cultivated low arousal" condition. Patients train to produce muscular relaxation by means of EMG feedback and to increase peripheral circulation by means of skin temperature feedback. To date some of our hypertensives have shown substantial pressure decrements; some have changed very little. Over the coming year a major focus of our effort will be to attempt to determine identifying characteristics of hypertensives likely to show substantial pressure in response to relaxation training.